The low-maintenance floors need only be swept or dry-mopped regularly and washed with a neutral cleaner. Although the finish can resemble glass, a clean surface is less slippery than an unpolished slab, independent tests reveal. It’s the dirt, dust or water that can cause a ball-bearing effect. For the safety conscious, there are products that can be applied to increase the slip resistance. Several companies make products specifically for polished concrete that contain special conditioning agents designed to help maintain the floor’s luster and to make it more oil and water repellant. Others make cleaners that contain sodium silicate, the same ingredient often used to densify floors during the initial polishing process. “The biggest advantage of polishing a floor is that it lets the floor breathe naturally,” says Walton, since there’s no coating to contend with. “This is a potential fix for any concrete that has vapor moisture transportation problems.” Most any structurally sound concrete floor can be polished, but keep in mind that visual defects that are present before may still be there afterward, albeit a lot shinier. If you’re lucky enough to plan for a polished floor from the bottom up, “The possibilities are endless,” says Greg Ferchaud, national sales manager of Seattle-based SASE Co. “While the concrete is being poured, you can add all sorts of things: different aggregate, seashells, screws, bolts, broken glass, marbles, whatever you want. Then when you start to grind it down, all these things start showing their faces.” With new pours, you have the option to integrally color the mix or stain it at any stage you pick. Some contractors also use shake-on color with good results, but this process tends to be a bit tricky. There are no hard and fast rules governing when to add color to an existing slab, Ferchaud says. “You can stain and polish existing concrete or you can polish and stain existing concrete, depending on the look you’re after.” Most of the jobs out there, however, involve polishing uncolored existing floors. “People are just starting to see the opportunity of planning ahead. I’d say nine out of 10 polishing jobs involve floors that weren’t meant to be polished,” he says.
“Stained concrete has been around for many years,” Ferchaud notes, while polishing concrete has really only taken off in the last three or four years. “Marrying the two together has become the new trend in the last year. It’s difficult to do.” But the end result is stunning. “First and foremost, you get a low-maintenance floor. It also just so happens to look great and last a very long time. The shine is just a plus.” Planetary polishers do it right Ferchaud, whose company SASE prides itself as a surface preparation equipment specialist, points out that most concrete slabs are not very level and have both high and low spots. To accommodate the typical slab’s shortcomings, a planetary polisher with a floating head system is your best bet. You need to have a machine with floating heads that follows the contour of the floor. This will allow you to increase production, shine and, ultimately, your bottom line.” Elna Beck, president of Leitch and Co./Intertool, a company in California specializing in stone-polishing equipment that it has adapted for the concrete industry, makes a variable speed side-driven planetary polisher that is designed to produce a flat, swirl-free finish on smaller areas including countertops and steps. She says her equipment is so easy to operate that you can move it across the material with one hand. And it’s very efficient. “It’ll produce a perfect finish five times faster than a single-head polisher,” she says. The company also makes a larger version, specifically for floors, that can grind, hone and polish. Like Beck and Ferchaud, Innovatech’s Walton is among the many that believe a variable speed, counter-rotating planetary grinder and polisher is critical to the concrete polishing process because it flattens and levels the floor better than anything else out there. Still, there is a lot of torque associated with the typical three-headed planetary polisher, he notes, adding, “It has a tendency to pull the equipment operator one way or another.” To combat this problem, Innovatech has developed a four-headed version which eliminates this torque. The company will debut the new counter-rotating grinder at the World of Concrete in Las Vegas in January 2005. Diamonds make it sparkle “To get that beautiful mirror finish without waves, you need to give that floor as much flatness as you possibly can,” explains VIC International’s Byrd. Each diamond grit forms its own “hills and valleys” scratch pattern, she says, and “A lot of people skip steps and buff in material in between changing diamonds. They’re just filling in the hills and valleys.” There are lots of things to consider when choosing which diamond to use, Byrd continues. Typically, you should start off with a 40-grit diamond that could be bonded soft, hard or normal. If you have a hard concrete floor, you need a softer bonded diamond. Conversely, if you have a soft concrete floor, you need a harder bonded diamond. Resin diamonds have a tendency to roll with the waves in a concrete floor, Byrd says, while metal bonds typically grind through that. “If you weren’t concerned about flattening the floor, you could just polish the surface with resin diamonds, but you wouldn’t get the best results.” Walton adds that he’s found that phenolic resin diamonds work better than other resins he’s tried. “They give the floor a much deeper shine,” he says. “They’re capable of making the light reflection look 10 feet deep.” To be truly successful, Ferchaud says, you need to let the concrete talk to you. “I don’t believe there’s a true formula for polishing concrete because every floor is different, every pour is different. Let the floor tell you when to use metal or resin and when you need to switch. Understanding concrete and diamonds will put you ahead of the competition.” 
Polishing: It’s not for everybody Contractors who are considering breaking into the polishing business, he adds, should be prepared to spend between $10,000 and $50,000 for a comprehensive equipment package. However, Hovis adds, just having the equipment isn’t enough. Contractors should consider “the total package” when selecting an equipment supplier, he stresses. “To maximize profits and overcome the learning curve associated with polishing concrete, contractors need the right equipment, superior diamond products and ongoing service and technical support.” Contractors across the country have plenty of good things to say about polishing concrete. “It’s a great alternative to surface coating and that’s what excites me the most,” says Rick Zingale of Centennial Surface Technology in Phoenix. “There are inherent problems with coatings,” adds Zingale, who’s been in the concrete repair business for eight years and has been polishing for the last two. “They’re hard to put down and lots of things can go wrong with them. Plus, their life span can be short depending on their use. The long-term advantages of the polishing process are incredible — and you get a heck of a nice floor out of it, too.” Shannon Ware, vice president of Concrete Restoration Inc. in Seattle, says the densifier also helps to lock in the color of an acid stain and harden the surface so that when you begin to polish you’re not removing color. For best results, he adds, a stain should be introduced during the higher level of the polishing process. Shane Siefken, general manager of Justrite Surfaces in Council Bluff, Iowa, says his crew typically applies the densifier after the 120- or 220-grit diamond application. All three men agree that the application of a densifier will slightly darken the color(s). Tooling options 
Zingale says he doesn’t use a planetary polisher but rather a 25-horsepower machine that is capable of doing bulk removal, diamond grinding and concrete polishing. Its four heads all spin in the same direction, he says, and he loves the results he’s been getting. “There’s a lot of talk about which machine is better, but I think the type of diamonds you use has more of an impact on the outcome than the equipment,” he says. The mix design, Ware says, also needs to be taken into account. Regardless of the machine, “It’s hard to get a consistent polish with lightweight concrete. It’s definitely not the preferred mix design for polishing.” True grit Siefken likens diamonds to sandpaper. “You don’t want to start out too smooth or you won’t remove the surface impurities.” 
He also adds that when he doesn’t want to expose the aggregate, he uses only resin diamonds. “That way I get more of a salt-and-pepper look rather than exposing aggregate that’s fingernail size.” Zingale estimates that about 90 percent of the work he does stops at an 800 grit. Ware says he also usually takes it up to 800, sometimes as high as 1,500. Both finishes meet the slip coefficient standards set by OSHA and ASTM. Wet or dry? Siefken prefers to do his polishing wet. “It’s messier than dry but the diamonds last longer and we get better results wet. We get a shinier finish when wet. But if the client is worried about mess, we’ll do it dry.” Ware, who has been polishing concrete for about four years, says his company polishes both wet and dry, depending on the project and stage of construction. 
Maintaining the shine Ware says he recommends a dry mop on a daily basis and, depending on traffic, a wet mop or an auto scrubber if it’s a big facility. “Keeping a polished floor clean is a lot cheaper than restripping the floor and putting something over it,” Zingale says. “When you don’t have to strip or replace worn-out VCTs [vinyl composition tiles] your client will enjoy a dramatic savings over a period of time.” Fentress says he’s very interested in the prospects of polishing and he sees a bright future for the finish. “There is a definite market for it,” he admits. “I just haven’t aggressively pursued it.”
|
||||||||||
Jim Walton, sales and training consultant for Innovatech Products & Equipment Co. Inc., a Seattle-based company that also specializes in surface prep equipment and supplies, echoes Byrd’s philosophy. “It’s typically a six- or seven-step process to bring the concrete up to a high sheen,” he says. And unlike the high gloss that can be achieved with any number of coatings, “This highly reflective appearance is all done mechanically.”
To properly polish a surface, she says, “The next tool you use must take out those hills and valleys and replace them with its own. Eventually the scratch patterns get very tiny and you wind up with a surface that is virtually flat.” And, if you combine all these steps with a good densifier that actually penetrates the concrete rather than just sits on the surface, you’ll create a hard and flat surface that is very wear resistant.
When he polishes, Zingale says he always uses a densifier, which is designed to tighten up concrete’s pores, prevent dusting and create a more abrasion-resistant surface. It also has similar properties to a sealer in that it helps prevent materials such as oil and chemicals from penetrating the surface. And, he adds, a densifier helps maintain luster and keep the surface shiny.
